1. Field of the Invention
One embodiment of the present invention disclosed in the specification, the drawings, and the claims (hereinafter referred to as “this specification and the like”) relates to a semiconductor device (e.g., a data retention circuit or a logic circuit), a driving method thereof, and a manufacturing method thereof. Note that one embodiment of the present invention is not limited to the above technical field.
2. Description of the Related Art
In order to reduce the power consumption of a semiconductor device, circuits that do not need to operate are stopped by power gating or clock gating. A flip-flop is a kind of sequential circuit (storage circuit that holds a state) included in a semiconductor device in many cases. Thus, a reduction in power consumption of the flip-flop is effective in reducing the power consumption of a semiconductor device including the flip-flop. When a general flip-flop is powered off, a state (data) retained therein is lost; therefore, it is necessary to back up the state of the flip-flop so that the semiconductor device is power gated.
For example, Non-Patent Document 1 discloses that the use of a flip-flop that includes a backup circuit including an oxide semiconductor transistor and a Si transistor enables power gating of a processor.